This change was needed because
lino.core.actors.Actor._collect_actions() now attaches also the
library actions, which caused the label property of the actors of
these to be read already during startup for these actions as
well. This caused a problem for actors with a dynamic label because
they do a database lookup (e.g. lino_book.projects.actors; en
passant I converted the index.rst file of that demo project to
The label of the actor). Oh yes, this is historically grown and
poorly documented code.

Another question was: Can teachers (in Lino Avanti) confirm an
enrolment? This is what changed with the new feature, and it made the
Avanti test suite fail. Laura should not have permission to confirm
that enrolment because the author is another user (nathalie) and Laura
is just a teacher.

Okay now I see. It’s because I added the SiteUser role to the Teacher user type. And that was
correct: teachers are site users.

The manager_roles_required attribute on Enrolment is not
SiteStaffbut:class:`SiteUser. It is defined as:

manager_roles_required=dd.login_required()

So it is “normal” that every site user can edit the state of
enrolments made by other users. It was rather a bug that in Avanti
this was not allowed because Teacher (by mistake) was lacking
the SiteUser role.